UC Irvine UC Irvine Previously Published Works Title Mutations of human NARS2, encoding the mitochondrial asparaginyl-tRNA synthetase, cause nonsyndromic deafness and Leigh syndrome. Permalink https://escholarship.org/uc/item/2dt5r3jw Journal PLoS genetics, 11(3) ISSN 1553-7390 Authors Simon, Mariella Richard, Elodie M Wang, Xinjian et al. Publication Date 2015-03-25 DOI 10.1371/journal.pgen.1005097 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California RESEARCH ARTICLE Mutations of Human NARS2, Encoding the Mitochondrial Asparaginyl-tRNA Synthetase, Cause Nonsyndromic Deafness and Leigh Syndrome Mariella Simon1,2☯, Elodie M. Richard3☯, Xinjian Wang4☯, Mohsin Shahzad3, Vincent H. Huang4, Tanveer A. Qaiser5, Prasanth Potluri6, Sarah E. Mahl7, Antonio Davila8, Sabiha Nazli5, Saege Hancock9, Margret Yu10, Jay Gargus11, Richard Chang2, a11111 Nada Al-sheqaih12, William G. Newman12, Jose Abdenur2, Arnold Starr13, Rashmi Hegde14, Thomas Dorn15, Anke Busch16, Eddie Park1, Jie Wu17, Hagen Schwenzer18, Adrian Flierl19, Catherine Florentz18, Marie Sissler18, Shaheen N. Khan5, Ronghua Li4, Min-Xin Guan4, Thomas B. Friedman20, Doris K. Wu21, Vincent Procaccio22, Sheikh Riazuddin23,24,25, Douglas C. Wallace6, Zubair M. Ahmed3, Taosheng Huang4*, Saima Riazuddin3* 1 Department of Developmental and Cellular Biology, School of Biological Sciences, University of California, Irvine, Irvine, California, United States of America, 2 CHOC Childrens’, Division of Metabolics, Orange, OPEN ACCESS California, United States of America, 3 Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America, 4 Division of Human Citation: Simon M, Richard EM, Wang X, Shahzad Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America, M, Huang VH, Qaiser TA, et al. (2015) Mutations of 5 National Center for Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan, 6 Center Human NARS2, Encoding the Mitochondrial for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology Asparaginyl-tRNA Synthetase, Cause Nonsyndromic and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America, Deafness and Leigh Syndrome. PLoS Genet 11(3): 7 Division of Pediatric Otolaryngology Head & Neck Surgery, Cincinnati Children’s Hospital Medical Center, e1005097. doi:10.1371/journal.pgen.1005097 Cincinnati, Ohio, United States of America, 8 Smilow Center for Translational Research, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America, 9 Trovagene, San Diego, California, Editor: Karen B. Avraham, Tel Aviv University, United States of America, 10 Marshall B Ketchum University, Fullerton, California, United States of America, ISRAEL 11 Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, United States of America, 12 Manchester Centre for Genomic Medicine, University of Manchester and Central Manchester Received: December 26, 2014 University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre (MAHSC), Manchester, United Kingdom, 13 Department of Neurology and Neurobiology, University of California, Irvine, Accepted: February 23, 2015 Irvine, California, United States of America, 14 Division of Developmental Biology, Cincinnati Children’s Published: March 25, 2015 Hospital Medical Center, Cincinnati, Ohio, United States of America, 15 Swiss Epilepsy Center, Zurich, Switzerland, 16 Institute of Molecular Biology, Mainz, Germany, 17 Institute for Genomics and Copyright: This is an open access article, free of all Bioinformatics, University of California, Irvine, Irvine, California, United States of America, 18 Architecture et copyright, and may be freely reproduced, distributed, Réactivité de l’ARN, CNRS, University of Strasbourg, IBMC, Strasbourg, France, 19 Parkinson’s Institute transmitted, modified, built upon, or otherwise used and Clinical Center, Sunnyvale, California, United States of America, 20 Laboratory of Molecular Genetics, by anyone for any lawful purpose. The work is made National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, available under the Creative Commons CC0 public Maryland, United States of America, 21 Section on Sensory Cell Regeneration and Development, National domain dedication. Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States of America, 22 Biochemistry and Genetics Department, UMR CNRS 6214–INSERM Data Availability Statement: All relevant data are U1083, CHU Angers, Angers, France, 23 Jinnah Hospital Complex, Allama Iqbal Medical College, University within the paper and its Supporting Information files. of Health Sciences, Lahore, Pakistan, 24 University of Lahore, Lahore, Pakistan, 25 Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan Funding: This study was supported by intramural funds from the NIDCD DC000039-17 to TBF, by an ☯ These authors contributed equally to this work. Action on Hearing Loss grant and by National * [email protected] (TH); [email protected] (SR) Institute on Deafness and Other Communication Disorders (NIDCD/NIH) research grants R01DC011803 and R01DC011748 to SR and R01DC012564 to ZMA. This work is supported in part by the UC Irvine Foundation, the S. Family Foundation and Cincinnati Children’s Hospital Research Foundation to TH, NIH grant NS21328, PLOS Genetics | DOI:10.1371/journal.pgen.1005097 March 25, 2015 1/26 NARS2 Mutations Cause Nonsyndromic Deafness and Leigh Syndrome Doris Duke Foundation grant 2005057, and Simons Foundation grant 205844 to DCW. This work was Abstract also partially supported by Centre National de la Here we demonstrate association of variants in the mitochondrial asparaginyl-tRNA synthe- Recherche Scientifique (CNRS), Université de NARS2 Strasbourg (UdS), and by the French National tase with human hearing loss and Leigh syndrome. A homozygous missense muta- Program “Investissement d’Avenir” [ANR-11-LABX- tion ([c.637G>T; p.Val213Phe]) is the underlying cause of nonsyndromic hearing loss 0057_MITOCROSS] to MSis. The project described (DFNB94) and compound heterozygous mutations ([c.969T>A; p.Tyr323*] + [c.1142A>G; was also supported by the National Center for p.Asn381Ser]) result in mitochondrial respiratory chain deficiency and Leigh syndrome, Research Resources and the National Center for Advancing Translational Sciences, National Institutes which is a neurodegenerative disease characterized by symmetric, bilateral lesions in the of Health, through Grant UL1 TR000153. The content basal ganglia, thalamus, and brain stem. The severity of the genetic lesions and their effects is solely the responsibility of the authors and does not on NARS2 protein structure cosegregate with the phenotype. A hypothetical truncated necessarily represent the official views of the NIH. * The funders had no role in the study design, data NARS2 protein, secondary to the Leigh syndrome mutation p.Tyr323 is not detectable and collection and analysis, decision to publish, or p.Asn381Ser further decreases NARS2 protein levels in patient fibroblasts. p.Asn381Ser preparation of the manuscript. also disrupts dimerization of NARS2, while the hearing loss p.Val213Phe variant has no ef- Competing Interests: The authors have declared fect on NARS2 oligomerization. Additionally we demonstrate decreased steady-state levels that no competing interests exist. of mt-tRNAAsn in fibroblasts from the Leigh syndrome patients. In these cells we show that a decrease in oxygen consumption rates (OCR) and electron transport chain (ETC) activity can be rescued by overexpression of wild type NARS2. However, overexpression of the hearing loss associated p.Val213Phe mutant protein in these fibroblasts cannot comple- ment the OCR and ETC defects. Our findings establish lesions in NARS2 as a new cause for nonsyndromic hearing loss and Leigh syndrome. Author Summary Mitochondrial respiratory chain (MRC) disease represents a large and heterogeneous group of energy deficiency disorders. Here we report three mutations in NARS2, a mito- chondrial asparaginyl-tRNA synthetase, associated with non-syndromic hearing loss (NSHL) and Leigh syndrome in two independent families. Located in the predicted cata- lytic domain of the protein, missense mutation p.(Val213Phe) results in NSHL (DFNB94) while compound heterozygous mutation (p.Tyr323Ã; p.Asn381Ser) is leading to Leigh syn- drome with auditory neuropathy. In vivo analysis deemed p.Tyr323Ã mutant protein to be unstable. Co-immunoprecipitation assays show that p.Asn381Ser mutant disrupts the di- merization ability of NARS2. Leigh syndrome patient fibroblasts exhibit a decreased steady-state level of mt-tRNAAsn. In addition, in these cells, the mitochondrial respiratory chain is deficient, including significantly decreased oxygen consumption rates and electron transport chain activities. These functions can be partially restored with over-expression of wild-type NARS2 but not with p.Val213Phe mutant protein. Our study provides new insights into the genes that are necessary for the function of brain and inner ear sensory cells in humans. Introduction Mitochondrial respiratory chain (MRC) disease represents a large and heterogeneous group of